"It is impossible to have an unbiased campaign when our news is being dominated by terrorism."

Roy Shepherdson added: "The General Election IS the target. Can't let them win. Postpone it a week."

And Nick Applewhite said: "Something must be done to postpone election. Third attack in three months is horrifying."

In 2001, Tony Blair had to postpone an entire election by a month because of an outbreak of foot-and-mouth disease.

Mr Blair had let it be known that he had pencilled in the election for May 3 to coincide with local council polls, but delayed the votes until June 7 because of the difficulty of campaigning while the animal disease was being contained.